Attic Mix Room...not quite a studio

Hey all - long time reader/lurker/researcher - fantastic sight/resource indeed! Anyways, i've been renovating my house over the last few years and finally got around to the attic...which will be my mix down room for the time being, until the kids arrive at least(a few years away I hope!).. For the space in my attic, I'm using about 2/3 of the entire space from where the stairs come up to the front dormer- Im going to treat the entire kneewalls/ceiling/walls the same for the whole thing but I haven't worked out the details of how i'm going to block off the stairs at the top or bottom... The kneewalls are 2x4's with top and bottom plates. The roof decking is OSB/Aspenite over the original 'plank' type decking with ashphalt shingles on top of all that...I need a new roof in the next few years and hopefully can put a metal one on there as they are supposedly quieter than ashphalt. The floor is 1" Tongue and Groove Hem-fir, and the attic floor/2nd floor ceiling are actually rough-hewn 2 1/2 x 4 1/2 beams - single boardsthat extend from soffit-tip to soffit-tip(22ft)! In the process of gutting and rebuilding the rest of the house these were sistered with 2x6's that were glued and screwed to the existing joists and notched to sit on top plates at both ends. The attic was just insulated(sprayfoam) all around a few months ago before the brutal Canadjian winter kicked in(and good thing...it's still going strong out there!) For now I'm trying to think how best to isolate myself from the outside world as well as the floor - I'm not thinking i'm going to float the floor or put a drummer up there while my wife tries to sleep below, it's going to be vocals/mixdown almost exclusively...most of the recording will happen elsewhere. I've done lots of reading on products from Sonopan to Quietrock to greenglue to various construction techniques - I have access to 'Quietrock' sheetrock or Quietglue(greenglue equivalent) and am very familiar with construction from framing to finishing...if there are more details needed just let me know! Note: I did read about linking photos off site and I will upload them here, but I have a photobucket account and can leave them on there until I resize the photos properly for now... Here's the layout of the room with dimensions....I'm not at the 'sketchup phase' yet... http://i2.photobucket.com/albums/y8/tungstengruvsten/th_atticdrawing.jpg And here's some pictures... http://i2.photobucket.com/albums/y8/tungstengruvsten/renovations/th_atticreno031.jpg http://i2.photobucket.com/albums/y8/tungstengruvsten/renovations/th_atticreno030.jpg http://i2.photobucket.com/albums/y8/tungstengruvsten/renovations/th_atticreno029.jpg http://i2.photobucket.com/albums/y8/tungstengruvsten/renovations/th_atticreno028.jpg

for vox, you'll want to worry mostly about the quality of the room sound and that would likely tend to be dryer (deader) than when recording an acoustic guitar (for example). so overhead absorption as well as the side/angled ceiling/walls will need treatment. a good quality exterior door with magnetic seals would work to close off the space but you'll want to consider HVAC with fresh air exchange as part of the design... foot impact can be reduced several ways. a carpet with padding works. heavy plywood over opencell polyurethane foam (like carpet padding :-)) works and keeps the floor lively. from an attic perspective - inbound noise like rain, hail etc would be annoying so maybe some RC on the joists/rafters and 1-2 layers of drywall w/ or w/o greenglue as budget allows.

awesome thanks for the reply gullfo- I don't have a lot of headroom for resilient channel/lotsa drywall for the cathedral parts but a couple layers of drywall and greenglue in between might happen. Right now the R-value of the cathedral ceiling is R27 - I might put 1" XPS insulation boards on this to block thermal transfer through the rafters(brings my R-value over 30 as well), if I green glue+screw quietrock onto this, with acoustic sealant wherever necessary, what kind of reduction can I expect? I've looked several times at Sonopan(it's R-value is around 3 but I'm suspecting it has better sound reduction properties than XPS) and drywall for the same spot....i know, i know, not really studio type talk but a balance between this being a well-insulated(from the heating/cooling perspective) and a well-isolated room is necessary...I've done just as much reading on the Mike Holmes site as here! On the kneewalls, should I put drywall on the other side of the kneewall as well? Also, would I benefit from putting down drywall/sonopan/something else on the floor area inside the kneewall to help with sound going downstairs? I've got tons of pink insulation to put in the kneewalls for heat/cool purposes, would it help sound at all to stuff this area as opposed to partial stuffing/airspace? For acoustics I have access to the Primacoustic line at cost through work...the Broadway line is mostly 703/705 style insulation with fabric over it, available in 1",2",3" thicknesses, as well as functional basstraps...How do I go about planning it's use in a room like this? I'm aware of the mirror/monitor trick, but with angled ceilings is there another method? I'm thinking of putting my monitors in the spots to the left/right of the dormer space - an equilateral triangle there would be about 80"/side, and I'd have room in the corner in behind it for some bass trapping...

the insulation itself won't help with isolation, a couple of layers of drywall and green glue (not an adhesive) would be do the trick. i would take the drywall all the way down the rafters to the floor and then use under the eaves for trapping or racks etc. the absorption planning sounds right - on the angled ceiling you will want to treat those for reflection points just like you would a side wall or ceiling. the rest of the space behind you can stagger the absorbers to break up the reflections and then concentrate some absorbers where you need reflection control for the vox.

gullfo wrote:

the insulation itself won't help with isolation, a couple of layers of drywall and green glue (not an adhesive) would be do the trick.

Gotcha - would it be worth it to build bass traps into the knee wall to the sides of the dormer? I saw this in another thread...this would be almost right behind speakers if I used larger ones on stands and not just nearfields... That raises another question that i'm not sure belongs here or not - but at what room size do nearfields become mid-fields? I have a pair of Dynaudio BM6a's and a BM15/QSC amp combo that I used at a previous studio, the 10" BM15's might be overkill in this room but it would be nice to have them there for the 'turn it up impress the client' times...how would you place these? (Again, I can edit this out and start a new thread elsewhere...)

sure, the knee walls are good places to tuck in bass trapping as well as a isocabinet for loud equipment. if the bm15s are to impress clients, put them on stands in front of the client couch so you can crank them... ;-) or if you want to use them to check your mix, then put them on stands in the front of the room, pop in ear plugs when its time to hype...